facebook.el

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;;; facebook.el --- Access the Facebook API from emacs
     
;;; Copyright (C) 2009 Paul Huff
     
;;; Author: Paul Huff <paul.huff@gmail.com>
;;; Maintainer: Paul Huff <paul.huff@gmail.com>
;;; Created: 5 Oct 2007
;;; Last modified: 3 Oct 2009
;;; Version: 0.0.3
;;; Package-Requires: ((json "0"))
;;; Keywords: facebook, frivolity

;; This file is NOT part of GNU Emacs.

;; This is free software; you can redistribute it and/or modify it under
;; the terms of the GNU General Public License as published by the Free
;; Software Foundation; either version 2, or (at your option) any later
;; version.

;; This file is distributed in the hope that it will be useful, but
;; WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
;; General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with Emacs; see the file COPYING, or type `C-h C-c'. If not,
;; write to the Free Software Foundation at this address:

;;   Free Software Foundation
;;   51 Franklin Street, Fifth Floor
;;   Boston, MA 02110-1301
;;   USA     

;;; Commentary:
;;; Version 0.0.3 A slight tweak to get login working properly no matter what.
;;;
;;; Version 0.0.2 Came out and had a bunch of patches from Rudi Schlatte.  Thanks, Rudi!  Seems like it works on ubuntu and mac os x for me now.
;;; 
;;;   First pass at interfacing with facebook.  You must add the "developers 
;;;   app" and get your own application api-key and application secret key to 
;;;   use this.  Also, facebook's authentication scheme is, well, ridiculous, 
;;;   so you've got to have gnutls or openssl installed, as well as a working
;;;   browser that handles https to log in and give your app permissions.
;;;   Also, it requires hober's excellent json.el which can be obtained here:
;;;   http://edward.oconnor.cx/elisp/json.el

;;;   To log into facebook, call (facebook-login)
;;;   To check credentials/optionally login call (facebook-check-creds)
;;;   To make api calls call (facebook-call-function "<funcname>" (list (cons "of" "args") (cons "more" "args")))

;;;   Only two actual api functions are present right now, (though you can 
;;;   use facebook-call-function to call whatever you'd like...):
;;;   facebook-users-has-app-permission = users.hasAppPermission
;;;   facebook-users-set-status = users.setStatus
;;;   facbeook-users-set-status checks for the applicable app permission 
;;;   redirects the user to the permission page if needed and then goes and 
;;;   updates the status.

;;;   The sf.net project homepage for this project can be found here:
;;;   http://sf.net/projects/facebook-el

;;; Code:
(require 'json)
(defcustom facebook-api-key "" "Your facebook api-key")
(defcustom facebook-api-secret "" "Your facebook api secret")
(defcustom facebook-session-info nil "Your facebook session info.  This will be set by facebook.el")

(defun facebook-current-time ()
  (let ((current-time (current-time)))
    (+ (* (car current-time) (float (expt 2 16))) (cadr current-time))))

(defun facebook-call-function-post (method-name args)
  "Send ARGS to URL as a POST request."
  (let* ((url "http://api.facebook.com/restserver.php")
         (url-request-method "POST")
         (url-request-extra-headers
          '(("Content-Type" . "application/x-www-form-urlencoded")))
         (full-args `(("method" . ,method-name)
                      ("v" . "1.0")
                      ("format" . "JSON") 
                      ("api_key" . ,facebook-api-key)
                      ("call_id" . ,(mapconcat 'number-to-string 
                                             (current-time) ""))
                      ,@args))
         (sorted-full-args (sort full-args
                                 (lambda (a b) (string< (car a) (car b)))))
         (secret
          (if (and facebook-session-info
                   (or (equal (assoc-default 'expires facebook-session-info) 0)
                       (<= (facebook-current-time)
                           (if (null (assoc-default 'expires facebook-session-info))
			       0
			     (assoc-default 'expires facebook-session-info))
			   ))
		   (not (string= method-name "auth.createToken")))
              (assoc-default 'secret facebook-session-info)
            facebook-api-secret))
         (sig-full-args `(("sig" . ,(facebook-create-sig sorted-full-args secret))
                          ,@sorted-full-args))
         (url-request-data
          (mapconcat (lambda (arg)
                       (concat (url-hexify-string (car arg))
                               "="
                               (url-hexify-string (cdr arg))))
                     sig-full-args
                     "&"))
         (result 
          (save-excursion
            (set-buffer (url-retrieve-synchronously url))
            (progn (goto-char (point-min))
                   (delete-region (point-min) (search-forward "\n\n"))
                   (buffer-substring (point-min) (point-max))))))
    (setq facebook-last-raw-json-result result)
    (json-read-from-string result)))

(defun facebook-create-sig (args-array secret)
  (let* ((request-str (mapconcat (lambda (arg)
                                   (concat (car arg) "=" (cdr arg)))
                                 args-array
                                 "")))
    (md5 (concat request-str secret))))

;;;###autoload
(defun facebook-login ()
  (interactive)
  (let* ((auth-token (facebook-call-function-post "auth.createToken" '()))
     (login-url (concat 
                 "https://login.facebook.com/login.php?v=1.0&api_key=" 
                 facebook-api-key "&auth_token=" auth-token)))
    (browse-url login-url)
    (read-string (format "Hit enter here after you've logged into facebook (this is their lame scheme, not facebook.el's %s" login-url))
    (customize-save-variable 'facebook-session-info 
                             (facebook-call-function-post "auth.getSession"  
                                                          (list (cons 
                                                                 "auth_token" 
                                                                 auth-token)))
                             )))


(defun facebook-check-creds ()
  (interactive)
  (let* ((session-expires 
          (assoc-default 'expires facebook-session-info nil -1))
         (current-time (facebook-current-time)))
    (if (not (equal session-expires 0))
        (if (or (null session-expires) 
                (<= session-expires current-time))
            (facebook-login)
          t)
      t)))

(defun facebook-users-has-app-permission (permission)
  (interactive)
  (let ((result 
         (facebook-call-function-post "users.hasAppPermission" 
                                      (list (cons "session_key" 
                                                  (assoc-default 
                                                   'session_key 
                                                   facebook-session-info)) 
                                            (cons "ext_perm" permission)))))
    (setq facebook-last-app-permission result)))


;;;###autoload
(defun facebook-users-set-status (status_message)
  (interactive)
  (progn
    (facebook-check-creds)
    (if (equal (facebook-users-has-app-permission "status_update") 0)
	(let* ((auth-url (concat 
			  "http://www.facebook.com/authorize.php?api_key="
			  facebook-api-key "&v=1.0&ext_perm=status_update"))) 
	  (progn
	    (browse-url auth-url)
	    (read-string "Hit enter here after you've granted your app_key permission to update your status (should only have to do this once... this is their lame scheme, not facebook.el's)")
	    )))
    (message "Setting status to: %s" status_message)
    (let ((result 
	   (facebook-call-function-post "users.setStatus" 
					(list 
					 (cons "session_key" 
					       (assoc-default 
						'session_key 
						facebook-session-info)) 
					 (cons "status" status_message)))))
      (setq facebook-set-status-result result))))

;;;###autoload
(defun facebook-status (status_message)
  (interactive  "sStatus message: ")
  (facebook-users-set-status status_message))


(defun facebook-users-get-info (uids fields)
  "Run users.getInfo.  uids are expected to be strings."
  (interactive)
  (progn 
    (facebook-check-creds)
    (facebook-call-function-post "users.getInfo"
				 (list 
				  (cons "session_key" 
					(assoc-default 
					 'session_key 
					 facebook-session-info))
				  (cons "uids" (mapconcat 'identity uids ","))
				  (cons "fields" (mapconcat 'identity fields ","))))))

(defun facebook-friends-get ()
  (interactive)
  (progn
    (facebook-check-creds)
    (facebook-call-function-post "friends.get"
				 (list
				  (cons "session_key"
					(assoc-default
					 'session_key
					 facebook-session-info)
					)))))
(defun facebook-get-friends-status ()
  (interactive)
  (progn
    (facebook-check-creds)
    (let* ((friends-uids (mapcar 'facebook-string-hack (facebook-friends-get)))
	   (friends-statuses (mapcar 
			      'identity 
			      (facebook-users-get-info 
			       friends-uids 
			       (list "name" "status")))))
      
      (with-output-to-temp-buffer "*Facebook status*"
	(set-buffer "*Facebook status*")
	(mapc (lambda (item)
		(let* ((status-time 
			(assoc-default 'time
				       (assoc-default 'status item)))
		       (status-message 
			(assoc-default 'message
				       (assoc-default 'status item)))
		       (ago (if status-time
				(- (float-time) 
				   (assoc-default 'time 
						  (assoc-default 
						   'status item)))
			      nil)))
		  (if (and status-time (not (string= status-message "")))
		      (if (< ago (* 24 3600))
			  (insert (concat (assoc-default 'name item) " "
					  status-message
					  "  (" 
					  (facebook-truncate (/ ago 3600.0))
					  " hours ago)\n"))))))
	      friends-statuses)
      )
      (setq facebook-last-friends-statuses friends-statuses))))

;;(facebook-friends-get-info)
(defun facebook-truncate (num)
  (let* ((my-string (number-to-string num))
	 (start (string-match (rx (group (1+ digit) "." (** 1 2 digit))) my-string))
	 (end (match-end 0)))
    (substring my-string start end)))


(defun facebook-string-hack (num)
  "Function for handling ridiculously large float to int conversions in emacs"
  "because facebook uses numbers larger than fs-most-positive-fixnum"
  (replace-regexp-in-string (rx "." (one-or-more digit) line-end) "" (number-to-string num)))


;;(setq my-facebook-update-time (facebook-users-get-info (list "723430982") (list "name" "status")))

;;(mapcar 'facebook-status-checker-mapfunc my-facebook-update-time)

;;(- current-time my-facebook-update-time)

(provide 'facebook)
;;; facebook.el ends here